Typically, gas turbine engines include a compressor for compressing air, a combustor for mixing the compressed air with fuel and igniting the mixture, and a turbine blade assembly for producing power. Combustors often operate at high temperatures that may exceed 2,500 degrees Fahrenheit. Typical turbine combustor configurations expose turbine vane and blade assemblies to these high temperatures. As a result, turbine vanes and blades must be made of materials capable of withstanding such high temperatures. In addition, turbine vanes and blades often contain cooling systems for prolonging the life of the vanes and blades and reducing the likelihood of failure as a result of excessive temperatures. Turbine engines typically include a plurality of rows of stationary turbine vanes extending radially inward from a shell and include plurality of rows of rotatable turbine blades attached to a rotor assembly for turning the rotor.
Row one turbine vanes may be axially supported at the ID end of the vanes. Such support schemes for row one turbine vanes should provide fail-safe support structures operable under extreme structural and thermal loading. Conventional support schemes include supporting the row one turbine vane at an OD shroud aft rail and at an ID shroud aft rail from the shaft cover positioned radially inward of the turbine vane. However, such an arrangement can lead to significant leakage at the aft rail because the tangential aero load on the vane can unseat the sealing surfaces at the airfoil concave side end of the aft rails, as shown in FIG. 1. Sealing the turbine vane to the forward end of the shrouds is also complicated because rotation of the turbine vane due to the tangential aero load creates differences in the axial location of the shroud forward end from one circumferential side of the shroud to the other, which is referred to herein as “sawtoothing.” The shaft cover ID support of the vane in many conventional support systems also serves as a seal between the combustor shell and the turbine blade rim cavity. The sealing function of this support is less effective then desired because of the aforementioned tendency of the aft sealing surfaces to separate. Thus, a need exists for a turbine vane support capable of supporting a turbine vane without allowing twisting about a radial axis to maximize the effectiveness of the seals.